There has been proposed a device that comprises both an exhaust heat recovery function for recovering heat from exhaust gas of an internal combustion engine and an EGR cooling function for cooling exhaust gas to be recirculated by an EGR that recirculates partially exhaust gas to an intake system of the internal combustion engine (see, for example, Patent Document 1). EGR is the abbreviation for Exhaust Gas Recirculation (i.e., exhaust gas recirculation.)
According to the technology described in Patent Document 1, exhaust gas discharged from the internal combustion engine is transmitted partially or fully to a heat exchanger in response to an opening degree of a valve, so that heat recovery and exhaust gas cooling are performed. The cooled exhaust gas is recirculated partially or fully to the intake system of the internal combustion engine via a first branch in response to the position of a changeover valve. When the exhaust gas is partially recirculated to the intake system of the internal combustion engine, the rest of the exhaust gas is partially transmitted to a central pipe via a second branch and is discharged to the outside of the system.